JP7292167B2 - TUBULAR BODY MANUFACTURING DEVICE AND MANUFACTURING METHOD - Google Patents

Description

TECHNICAL FIELD The present invention relates to a manufacturing apparatus and manufacturing method for manufacturing a tubular body with an open end from a closed tube with a closed end.

In industrial products such as automobiles and buildings such as houses, hose-like tubular bodies for circulating fluids such as air are installed in various places. It's being used. The tubular body is a curved hollow molded body that is appropriately meandering in accordance with its mounting location, and is molded by blow molding such as direct blow, injection blow, or suction blow. In this suction blow, a cylindrical parison is inserted into the cavity from one open end of the closed mold, air inside the cavity is sucked from the other end of the mold, and placed in the mold. It is a technique for molding, and has the advantage of being able to easily form a bent tubular body according to the shape of the mold cavity.

A blow-molded product formed by blow molding has closed ends and cannot be used as a tubular body as it is, so the closed ends (discard bag) are cut off and removed. As a device for cutting such a waste bag, for example, as disclosed in Patent Document 1, a rotary cutter such as a circular saw is cut in the outer peripheral direction of the blow-molded product while the blow-molded product having the waste bag is held at a predetermined position. A device that cuts a waste bag by revolving in a circle or, as in Patent Document 2, a plate-shaped blade having a cutting edge at the lower end is pressed from above while a blow-molded product having a waste bag is held at a predetermined position. Devices for cutting bags are known.

Japanese Patent Publication No. 5-43469 JP-A-5-237793

By the way, when a disposal bag of a blow-molded product is cut by a rotary cutter as in the apparatus of Patent Document 1 mentioned above, it is inevitable that chips generated during the cutting process enter the inside of the bag. If such shavings remain inside the tubular body, the shavings will fly in the process of fluid circulation and adversely affect the connecting point of the tubular body. It is necessary to provide a removal step to remove shavings from the interior of the tubular body. However, when the tubular body has a bent shape or a shape having a bellows-like portion in the middle of the pipe, there is a problem that cutting chips are caught on the bent portion or the bellows-like portion and it takes time and effort to remove them by air blowing or washing with water. There is Furthermore, cutting chips that have softened under the influence of frictional heat during cutting by the rotary cutter adhere to the inside of the tubular body and harden, making it difficult to completely remove the cutting chips. In addition to the problems caused by cutting chips, the rotation of the rotary cutter causes the waste bag to shake during cutting, which causes distortion such as oblique or wavy cut surfaces, resulting in high-precision cutting. It is difficult and the distortion becomes noticeable especially towards the terminal stage of cutting. The swaying movement of the waste bag, which causes such distortion of the cut surface, can be suppressed by pressing the end of the waste bag with a backing plate or the like. increases, and cutting chips tend to soften due to the effects of frictional heat during cutting.

On the other hand, as in the apparatus of Patent Document 2, when a plate-shaped blade is pressed against the blow-molded product from above to push and cut the disposal bag, the generation of cutting waste can be prevented in the cutting process, but cutting Large elastic deformation occurs when pressure is applied from one direction. For this reason, as in the case of cutting with a rotary cutter, the cut surface is slanted or wavy, which makes it difficult to cut with high accuracy. In particular, in a blow-molded product made of a soft resin, the distortion of the cut surface becomes noticeable.

That is, an object of the present invention is to provide an apparatus and method for manufacturing a tubular body that suppresses generation of shavings and distortion of a cut surface when cutting a closed end of a closed tube.

In order to overcome the above problems and achieve the intended purpose, the invention according to claim 1 of the present application is
A manufacturing device for manufacturing a tubular body by cutting a closed end of a closed tube,
a plurality of cutters spaced apart around the rotation axis and having a cutting blade at the end on the rotation axis side;
a rotating part that rotates the plurality of cutters around the rotation axis with the cutting blades facing toward the rotation axis;
an advancing/retreating moving unit that advances/retracts the plurality of cutters so as to approach and separate from the rotation axis;
In a state where the closed tube is held inside surrounded by the plurality of cutters, the cutter is rotationally moved around the rotation axis and moved forward so as to approach the rotation axis to cut the closed end of the closed tube. The summary is that
In this way, by rotating the cutter around the rotation axis and moving forward so as to approach the rotation axis, it is possible to suppress the generation of chips when cutting the closed end of the closed tube. Then, it becomes possible to simplify or omit the work of removing the chips. In addition, since the swinging movement of the disposal bag during cutting can be suppressed, distortion of the cut surface after cutting can be suppressed. Furthermore, by rotating a plurality of cutters around the rotation axis to cut the closed tube, it is possible to suppress the frictional heat during cutting and prevent softening of cutting waste. In addition, by rotating around the cylindrical wall while a plurality of cutters are abutting against each other, the cutting pressure can be distributed to suppress the elastic deformation of the waste bag, and the cut surface can be made with less distortion.

The invention according to claim 2 is
By arranging the cutters at equal intervals around the rotation axis,
The gist is that the cutter is rotationally moved by an angle equal to or greater than an angle obtained by adding a rotational angle from the start of rotational movement until the cutting blade penetrates the cylindrical wall of the closed tube to the arrangement interval angle of the cutter. do.
In this way, the non-penetrating groove formed in the cylindrical wall from the start of the rotational movement until the cutting edge of the cutter end penetrates the cylindrical wall of the closed tube is attached to the cutter that formed the groove. It can be cut with a subsequent cutter positioned behind in the direction of rotational movement.

The invention according to claim 3 is
The cutter is configured to rotate forward and backward about a rotation axis between an initial rotation position and a rotary cutting position by the rotating portion,
The cutter is rotated and moved forward from the initial rotation position toward the rotary cutting position to cut the closed end of the closed tube, and after the cutting blade is moved backward to the outside of the cylinder wall, the cutter is moved to the initial rotation. The gist is to rotate toward a position.
In this way, after cutting the closed end of the closed tube, the cutting blade at the end of the cutter is moved backward to the outside of the cylinder wall, and then the cutter is rotated toward the initial rotation position, thereby cutting the cutting edge on the cut surface. can be prevented from coming into contact with the cutter, and the generation of shavings during the return of the cutter to the initial rotation position can be prevented.

The invention according to claim 4 is
The cutter is configured to rotate forward and backward about a rotation axis between an initial rotation position and a rotation cutting position by the rotating portion,
The cutter is moved forward while rotating from the initial rotation position toward the rotary cutting position to cut the closed end of the closed tube, and the cutter is rotated in a state in which the cutting blade protrudes inside the cylinder wall. The gist is that the cutting blade is moved backward to the outside of the cylinder wall after being rotated toward the position.
In this way, after cutting the closed end of the closed tube, the cutting edge of the cutter end is rotated toward the initial rotation position in a state of protruding inside the tube wall, and then the cutting edge is moved outside the tube wall. By moving backward, even if a non-penetrating groove remains, it is possible to cut the remaining non-penetrating groove with the cutting blade in the process of rotating towards the initial rotation position.

In order to overcome the above problems and achieve the intended purpose, the invention according to claim 5 of the present application is
A manufacturing method for manufacturing a tubular body by cutting a closed end of a closed tube,
With the cutting blade provided at the tip of the cutter in contact with the outer surface of the cylindrical wall of the closed tube, the cutter is rotated around the cylindrical wall and moved forward so that the cutting blade penetrates the cylindrical wall. The gist is to cut the closed end of a closed tube to manufacture a tubular body with an open end.
In this way, by rotating the cutter around the rotation axis and moving forward so as to approach the rotation axis, it is possible to suppress the generation of chips when cutting the closed end of the closed tube. Then, it becomes possible to simplify or omit the work of removing the chips. In addition, since the swinging movement of the disposal bag at the time of cutting can be suppressed, the distortion of the cut surface after cutting can be suppressed. Furthermore, by rotating a plurality of cutters around the rotation axis to cut the closed tube, it is possible to suppress the frictional heat during cutting and prevent softening of cutting waste. In addition, by rotating around the cylinder wall while a plurality of cutters are abutting against each other, the cutting pressure can be distributed to suppress elastic deformation of the waste bag, and the cut surface can be made with less distortion.

The invention according to claim 6 is
The cutters are arranged at regular intervals around the axis of rotation, and the rotation angle from the start of rotation of the cutter until the cutting edge penetrates the cylindrical wall of the closed tube is added to the arrangement interval angle of the cutter. The gist is that it is rotated by
In this way, the non-penetrating groove formed in the cylindrical wall from the start of the rotational movement until the cutting edge of the cutter end penetrates the cylindrical wall of the closed tube is attached to the cutter that formed the groove. It can be cut with a subsequent cutter positioned behind in the direction of rotational movement.

The invention according to claim 7 is
The gist is that after cutting the closed end of the closed tube, the cutting blade is retracted to the outside of the cylinder wall, and then the cutter is rotated to return to the initial rotation position.
In this way, after cutting the closed end of the closed tube, the cutting blade at the end of the cutter is moved backward to the outside of the cylinder wall, and then the cutter is rotated toward the initial rotation position, thereby cutting the cutting edge on the cut surface. can be prevented from coming into contact with the cutter, and the generation of shavings during the return of the cutter to the initial rotation position can be prevented.

The invention according to claim 8 is
After cutting the closed end of the closed tube, the cutter is rotated so as to return to the initial rotation position in a state in which the cutting blade protrudes inside the cylinder wall, and then the cutting blade is retracted to the outside of the cylinder wall. The gist is that
In this way, after cutting the closed end of the closed tube, the cutting edge of the cutter end is rotated toward the initial rotation position while protruding inside the cylinder wall, and then the cutter is retracted outside the cylinder wall. By moving, even if a non-penetrating groove remains, it is possible to cut the remaining non-penetrating groove with the cutting blade in the process of rotationally moving toward the initial rotation position.

ADVANTAGE OF THE INVENTION According to this invention, the distortion of the cut surface of a tubular body can be suppressed, preventing generation of cutting waste at the time of cutting a closed end.

1 is a schematic side view of a tubular body manufacturing apparatus according to the present invention, in which (a) shows a state in which a holding member is in a retracted position and a cutter is in a standby position, and (b) is a state in which the holding member is in a cutting position; , and the cutter is in the penetrating position. It is explanatory drawing which shows a holding member. It is a sectional view of a holding member. FIG. 4 is a front view of the cutting section, where (a) shows the cutter at the standby position, and (b) shows the cutter at the penetration position. FIG. 10 is an explanatory view showing a process of cutting the disposal bag;

Next, preferred embodiments of the tubular body manufacturing apparatus and manufacturing method according to the present invention will be described below with reference to the accompanying drawings. In this embodiment, a configuration for manufacturing a tubular body that can be suitably used as an air cleaner hose will be described as an example. This tubular body is molded by various blow molding such as conventionally known suction blow molding using synthetic resin or rubber as a raw material, and the ends are closed before being processed by the manufacturing apparatus and manufacturing method according to the present invention. The blow-molded article 50 in the state of being a tubular body having an open end is obtained by cutting the closed end (hereinafter referred to as "disposal bag 52") by the manufacturing apparatus and manufacturing method according to the present invention.

As shown in FIG. 1 , in the tubular body manufacturing apparatus 10 according to the embodiment, the closed end (discard bag 52 ) of the blow-molded product 50 held by the holding device 12 for holding the blow-molded product 50 is cut by the cutting device 30 . configured to disconnect. The holding device 12 includes a first holding member 14 that supports the tubular wall 50a of the blow-molded product 50 from below, and a second holding member 16 that supports the tubular wall 50a of the blow-molded product 50 from above. A second holding member 16 is connected to the first holding member 14 via a hinge 18 (see FIG. 2) provided on one side, and the second holding member 16 is closed on the other side. Locking means 20a, 20b are provided to hold the state. Various configurations can be adopted as the configuration of this locking means. is provided with a second engaging portion 20b having a hole into which the first engaging portion 20a can be inserted and removed, and the first engaging portion 20a and the second engaging portion 20b are engaged. The first holding member 14 and the second holding member 16 are held in a closed state by being brought together, and the second holding member 16 can be released from the first holding member 14 by releasing the engagement. It's becoming

As shown in FIG. 2, the first holding member 14 is formed with a semicircular first concave portion 14a that opens upward, and the second holding member 16 has a downward opening in the closed state. A second recessed portion 16a is formed in a semicircular shape, and the first recessed portion 14a and the second recessed portion 16a form a circular opening that matches the outer circumference of the cylindrical wall 50a of the blow-molded product 50. . Here, the blow-molded product 50 from which the disposal bag 52 is cut by the manufacturing apparatus 10 of the present embodiment is arranged so that the annular projection 50b protrudes from the cylinder wall 50a in accordance with the planned cutting position where the disposal bag 52 is to be cut. Annular stepped portions 14b and 16b (see FIG. 3) are formed on the inner peripheral surfaces of the first recessed portion 14a and the second recessed portion 16a, respectively. there is That is, with the second holding member 16 opened, the annular protrusion 50b of the blow-molded product 50 is fitted into the annular stepped portion 14b of the first recess 14a, and the second holding member 16 is closed to close the second recess 16a. By fitting the annular protrusion 50b into the stepped portion 16b, the blow-molded product 50 is held between the first holding member 14 and the second holding member 16 so that the disposal bag 52 protrudes as shown in FIG.

The holding members 14 , 16 holding the blow-molded product 50 are configured to be movable toward and away from the cutting device 30 by a moving means 24 . Specifically, in the embodiment, an air cylinder is used as the moving means 24, and the support member 22 connected to the first holding member 14 is connected to the cylinder rod of the air cylinder. That is, the holding members 14 and 16 can be moved by the moving means 24 between a cutting position where the discard bag 52 of the held blow-molded product 50 can be cut by the cutting device 30 and a retracted position retracted from the cutting position. . In this embodiment, the holding members 14, 16 are moved in the centerline direction CR1 of the circular opening formed by the first recess 14a and the second recess 16a. The moving means 24 for the holding members 14 and 16 is not limited to the air cylinder, and other types of cylinders such as hydraulic cylinders and conventionally known means such as motors can be employed. The holding members 14 and 16 may be configured to be movable between the cutting position and the retracted position by operation.

The cutting device 30 also includes a cutting section 32 having a cutter 40 for cutting the disposal bag 52 of the blow-molded product 50 and a rotation support section 42 for rotatably supporting the cutting section 32 . The cutting part 32 has a plurality of moving bodies (advance and retreat movement parts) that can move linearly so as to approach and separate from the rotation axis CR (the center of rotation of the cutting part 32) on the front end side of the main body part 34 of the cutting part 32. 36 are provided radially, and each movable body 36 is interlocked and moved synchronously by an operating mechanism (not shown) provided inside the main body 34 . Here, in the embodiment, three moving bodies 36 are arranged at regular intervals (that is, at intervals of 120°) around the rotation axis CR. Although the operating mechanism of the cutting portion 32 is not particularly limited, in this embodiment, it is configured to move the moving body 36 by means of an air cylinder. Conventionally known mechanisms as disclosed in Japanese Patent No. 105375 can be employed. The mechanism for moving the moving body 36 may be electrically operated by a motor or the like.

A base member 38 projecting forward is attached to the front surface of each moving body 36 , and a cutter 40 is attached to the front end of the base member 38 . That is, in the cutting device 30 of the embodiment, a plurality (three) of cutters 40 are arranged at equal intervals (120° intervals) around the rotation axis, and the ends (tips) of the cutters 40 on the rotation axis CR side is provided with a cutting blade 40a. That is, the stand member 38 separates the cutters 40 from the front surface of the main body 34 so that when the blow-molded product 50 is moved to the cutting position, the cutters 40 do not interfere with the main body 34 and are surrounded by the plurality of cutters 40 . A disposal bag 52 can be placed on the inner side. Then, in a state in which the disposal bag 52 faces the inside surrounded by the cutter 40, the standby position (Fig. 1(a), Fig. 4(a)) where the cutting edge 40a of the cutter 40 is positioned outside the planned cutting position of the disposal bag 52. )), and a penetration position (see FIGS. 1(b) and 4) where the cutting blade 40a protrudes from the stand-by position to the inner surface side of the cylindrical wall 50a of the blow-molded product 50 (discard bag 52) close to the rotation axis CR side. (b)) and a plurality of cutters 40 are configured to move synchronously. That is, the cutting device 30 can cause the cutter 40 to move forward from the standby position to the penetration position and to move backward from the penetration position to the standby position in accordance with the operation of the operating mechanism. Further, the cutter 40 is formed with cutting blades 40a on both sides in the direction of rotation of the rotation support portion 42, so that the cutter 40 can cut the disposal bag 52 regardless of the direction of rotation of the rotation support portion 42. there is

In addition, the rotation support part 42 is provided with an annular rotating body (rotation part) 46 on the front surface of the main body part 44 of the rotation support part 42, and is rotated by an operating mechanism (not shown) provided inside the main body part 44. The body 46 is adapted to rotate. The body portion 34 of the cutting portion 32 is fixed to the front surface of the rotating body 46, and the cutting portion 32 (cutter 40) rotates as the rotating body 46 rotates. Here, the cutting unit 32 is attached so that the center of the cutting blades 40a of the radially arranged cutters 40 faces is positioned on the rotation axis CR of the rotor 46, and as the rotor 46 rotates, the rotation axis CR side The cutter 40 is configured to rotate around the rotation axis with the cutting blade 40a directed toward the front. As the operating mechanism of the rotation support part 42 of this embodiment, a rotary actuator is employed in which the rotating body 46 is rotated within a predetermined angular range by an air cylinder. It may be electrically operated.

Here, the holding device 12 and the cutting device 30 are arranged so that the circular opening center (opening center line CR1) formed by the concave portions 14a and 16a of the holding members 14 and 16 (the first holding member 14 and the second holding member 16) is positioned on the rotation axis CR of the cutter 40 (rotating body 46 of the rotation support part 42), and the holding members 14 and 16 are linearly moved along the rotation axis CR by the operation of the moving means 24. there is That is, by moving the holding members 14 and 16 to the cutting position by the operation of the moving means 24, the cutter 40 is moved outside the intended cutting position of the disposal bag 52 of the blow-molded article 50 held by the holding members 14 and 16. can be positioned.

Then, the cutting device 30 of this embodiment rotates the cutter 40 from a predetermined rotational initial position to the rotational cutting position, and advances the cutter 40 from the standby position toward the penetration position so as to approach the rotation axis CR, thereby performing a cutting operation. The operating mechanisms of the cutting portion 32 and the rotary support portion 42 are operated to perform the operation. That is, in a state in which the cutting edge 40a provided at the tip of the cutter 40 is in contact with the outer surface of the cylinder wall 50a of the blow-molded product 50, the cutter 40 is rotated around the cylinder wall 50a so that the cutting edge 40a cuts the cylinder wall 50a. By moving forward to penetrate, the disposal bag 52 of the blow molded article 50 is cut into a tubular body with an open end. 4 shows a state in which the cutter 40 is at the initial rotation position, and the cutter 40 rotates from this position toward the rotary cutting position in the clockwise direction in FIG. , the cutter 40 rotates in the counterclockwise direction in FIG.

Here, as shown in FIG. 5, until the cutter 40 with the cutting blade 40a in contact with the tubular wall 50a of the disposal bag 52 of the blow-molded product 50 advances by the thickness T of the tubular wall 50a, the cutter 40 A non-penetrating groove MA is formed by the rotation of , and a penetrating groove MB is formed by rotating the cutter 40 after the cutting edge 40a of the cutter 40 penetrates the cylindrical wall 50a. Then, the disposal bag 52 is cut by connecting the penetrating grooves MB formed by the respective cutters 40 . Therefore, the rotational movement angle θ at which each cutter 40 rotates from the initial rotation position to the rotational cutting position (the rotation angle of the rotating body 46 of the rotation support portion 42) is When the rotation angle until the cutting blade 40a penetrates the tubular wall 50a of the tubular body is defined as a penetration rotation angle θ1, the penetration rotation angle θ1 is added to the arrangement interval angle α of the cutter 40, or more. be. That is, each cutter 40 has a non-penetrating groove MA formed in the cylindrical wall 50a from the start of the rotational movement until the rotation angle reaches the penetrating rotation angle θ1, and the cutter 40 has an arrangement interval angle of α or more. A penetrating groove MB is formed at an angle of . As a result, the non-penetrating grooves MA formed by the cutters 40 located on the front side in the direction of rotational movement are cut by the subsequent cutters 40 located on the rear side in the direction of rotational movement, and the grooves MA formed by the respective cutters 40 are in the penetrating state. are connected to each other and the disposal bag 52 is cut. In FIG. 5 , the cutter 40 located on the front side in the rotational movement direction with respect to the cutter 40 indicated by the solid line and the non-penetrating groove MA formed by the cutter 40 are indicated by the two-dot chain line.

Specifically, when cutting the disposal bag 52 of the blow-molded product 50, when the rotary movement of the cutter 40 around the rotation axis CR and the forward movement from the standby position to the penetration position are started at the same time, The separation distance L [m] from the cutting blade 40a of the cutter 40 to the planned cutting position of the disposal bag 52 in a certain state, the design thickness T [m] of the disposal bag 52 at the planned cutting position, the rotational movement speed V1 [ rad/s] and the feed speed of the cutter 40 from the standby position to the penetration position is V2 [m/s], the penetration rotation angle θ1 [rad] is θ1=V1×(L+T)/V2. Further, when starting the forward movement from the standby position to the penetration position after starting the rotational movement of the cutter 40 around the rotation axis CR, or when starting the forward movement from the standby position to the penetration position before starting the rotational movement. In this case, the penetrating rotation angle θ1 increases or decreases depending on the time difference between the start of the rotational movement and the forward movement. Therefore, when the time difference from the start of the rotational movement to the start of the forward movement is S [s], the penetration rotation angle θ1 [rad] is θ1=V1×{( L+T)/V2+S}. Note that the time difference S when the forward movement is started before the rotational movement is a negative value. Further, when the forward movement from the standby position to the penetration position is started before starting the rotational movement, the rotational movement should be started before the cutting edge 40a of the cutter 40 comes into contact with the cylindrical wall 50a of the blow-molded product 50. is preferred. As a result, when the cutting edge 40a of the cutter 40 comes into contact with the outer surface of the cylinder wall 50a of the blow-molded product 50, the cutter 40 moves forward while rotating around the cylinder wall 50a. It is possible to effectively prevent the cutting pressure from the cutting blade 40a striking against the cylindrical wall 50a from concentrating on one point.

Here, when actually cutting the blow-molded product 50 and the disposal bag 52, there is an error between the design value and the actual size, and the rotation speed and the feed speed are completely constant due to the effects of the startup lag of the device. In addition, due to the nature of blow molding, the thickness T of the cylindrical wall 50a (position to be cut of the disposal bag 52) becomes uneven in the circumferential direction. Even if it rotates, the cutting blade 40a may not penetrate the cylinder wall 50a. That is, when the number of installed cutters 40 is N (N=3 in the embodiment), the arrangement interval angle α of the cutters 40 is 2π/N [rad], so the rotational movement angle θ [rad] of the cutters 40 is is preferably θ≧(2π/N+θ1). In this embodiment, the rotational movement angle θ of the cutter 40 is set to 240°.

After the cutting operation of cutting the disposal bag 52, the cutting device 30 operates the operating mechanisms of the cutting part 32 and the rotation support part 42 so that the cutter 40 returns to the initial rotation position and the standby position. be done. Here, as this return operation, after cutting the disposal bag 52 , the cutter 40 is rotated (reversely rotated) from the rotary cutting position toward the initial rotation position, before the cutter 40 is moved to the cylinder wall 50 a of the blow-molded product 50 . After that, the rotation support part 42 can be reversely rotated to return to the rotation initial position. By previously retracting the cutting edge 40a of the cutter 40 to the outside of the cylindrical wall 50a of the blow-molded article 50 in this manner, the cutting edge 40a of the cutter 40 can be prevented from touching the cut surface of the blow-molded article 50. There is an advantage that it is possible to prevent the generation of chips due to contact of the cutting edge 40a of the cutter 40 with the cut surface. In this case, it is not necessary to move the cutter 40 to the standby position. 42 may be reversely rotated.

As for the return operation, the cutter 40 is rotated in the reverse direction while the cutting edge 40a of the cutter 40 protrudes toward the inner surface of the cylinder wall 50a of the blow-molded product 50 to return to the initial rotation position. A retraction movement may be provided to return to the standby position. In this case, even if an uncut non-penetrating groove MA remains after the cutter 40 is rotationally moved at the rotational movement angle θ due to the influence of uneven thickness of the cylindrical wall 50a, the cutting blade 40a of the cutter 40 is protruded toward the inner surface of the cylindrical wall 50a of the blow-molded product 50, the rotation support portion 42 is reversely rotated, and the non-penetrating groove MA is cut by the cutter 40, which is reversely rotated. has the advantage of being able to separate In this case, the cutter 40 may start to move backward while the rotation support portion 42 is rotated in the reverse direction and returned to the initial rotation position.

Next, a method for manufacturing a tubular body according to an embodiment will be described using the manufacturing apparatus 10 described above.

With the holding members 14 and 16 of the holding device 12 positioned at the retracted position, the second holding member 16 is released from the first holding member 14, and the annular stepped portion of the first concave portion 14a of the first holding member 14 is opened. 14b is fitted with the annular projection 50b of the blow-molded product 50, and then the second holding member 16 is closed so that the annular projection 50b is fitted into the annular stepped portion 16b of the second recess 16a, whereby the disposal bag 52 protrudes. The blow-molded product 50 is held by the first holding member 14 and the second holding member 16 as shown. Then, with the cutters 40 of the cutting device 30 positioned at the standby position and the rotation initial position, the moving means 24 is operated to move the holding members 14 and 16 holding the blow-molded product 50 to the cutting position.

Next, the cutting portion 32 and the rotary support portion 42 are actuated so that the cutter 40 is rotated from the initial rotation position to the rotary cutting position and moved forward from the standby position to the penetration position to perform the cutting operation. That is, the cutting edge 40a of the cutter 40 is brought into contact with the outer surface of the cylindrical wall 50a of the disposal bag 52 of the blow-molded product 50, and the cutter 40 is moved along the cylindrical wall 50a while the cutting edge 40a is in contact with the cylindrical wall 50a. The cutting blade 40a is advanced so as to pass through the cylindrical wall 50a while being rotated around. At this time, each cutter 40 is rotationally moved at a rotational movement angle θ that is equal to or greater than an angle obtained by adding the penetrating rotational angle θ1 to the arrangement interval angle α of the cutters 40 from the rotational initial position to the rotational cutting position. The disposal bag 52 is cut.

After cutting the disposal bag 52 by moving the cutter 40 to the rotary cutting position and the penetrating position, the cutting portion 32 and the rotary support portion 42 are moved so as to return the cutter 40 to the initial rotation position and the standby position. The actuation mechanism is activated. As described above, this return operation is performed by moving the cutting edge 40a of the cutter 40 toward the blow-molded product 50 before rotating the cutter 40 from the rotary cutting position toward the initial rotation position (reverse rotation) after cutting the disposal bag 52 as described above. This can be done by moving backward to the outside of the cylinder wall 50a, and then rotating the rotation support portion 42 in the reverse direction to return to the initial rotation position. In the return operation, the cutter 40 is reversely rotated to return to the rotation initial position in a state in which the cutting edge 40a of the cutter 40 protrudes toward the inner surface of the cylinder wall 50a of the blow-molded product 50, and then the cutter 40 returns to the standby position. It is also possible to move backward so as to return to . After moving the cutter 40 to the standby position and the initial rotation position, the holding members 14 and 16 are moved from the cutting position to the retracted position, and the second holding member 16 is released from the first holding member 14. A tubular body in which the disposal bag 52 is cut is obtained.

In this way, while rotating the cutter 40 around the rotation axis CR so as to rotate the cutter 40 with the cutting edge 40a in contact with the cylindrical wall 50a (discard bag 52) of the blow-molded product 50, the cutter 40 is rotated around the cylindrical wall 50a. By moving forward so as to approach the rotation axis CR, it is possible to suppress the swinging motion of the disposal bag 52 at the time of cutting, so that a cut surface with little distortion can be formed. At this time, the tubular wall 50a of the blow-molded product 50 is gripped by the plurality of cutters 40 arranged at equal intervals, so that the swinging movement of the disposal bag 52 can be effectively suppressed. Further, by rotating around the cylindrical wall 50a while a plurality of cutters 40 are abutting against each other, the cutting pressure applied by the cutters 40 can be distributed, and elastic deformation of the disposal bag 52 during cutting can be suppressed. . Further, by cutting the disposal bag 52 by cutting the cylindrical wall 50a of the blow-molded product 50 with the cutting edge 40a of the cutter 40, the generation of cutting chips can be suppressed during the cutting process. can be simplified or omitted.

Further, the disposal bag 52 can be cut by moving the cutter 40 from the rotation initial position to the rotation cutting position, and the time during which the cutter 40 contacts the cut surface can be shortened. Therefore, even if cutting chips are generated during cutting, the cutting chips can be prevented from softening due to the frictional heat generated during cutting, and the cutting chips will firmly adhere to the inner surface of the tubular body (blow-molded product 50). can be prevented and can be removed easily.

Further, the rotational movement is equal to or greater than the angle obtained by adding the penetrating rotational angle θ1 from the start of rotational movement until the cutting edge 40a of the cutter 40 penetrates the cylindrical wall 50a of the blow-molded product 50 to the arrangement interval angle α of the cutter 40. By rotationally moving the cutter 40 at an angle θ, the non-penetrating groove MA formed in the cylindrical wall 50a of the blow-molded product 50 from the start of the rotational movement until the cutter 40 penetrates the cylindrical wall 50a is The cutting can be performed by the subsequent cutter 40 located behind the cutter 40 forming the groove portion in the direction of rotational movement.

Furthermore, in the return operation, after cutting the disposal bag 52 on the cylinder wall 50a of the blow-molded product 50, the cutting blade 40a of the cutter 40 is moved backward to the outside of the cylinder wall 50a, and then the cutter 40 is turned to the initial rotation position. In the case of rotational movement, the cutter 40 can be prevented from coming into contact with the cut surface during the return operation, and cutting waste can be prevented from being generated while the cutter 40 is being returned to the initial rotation position. Further, after cutting the disposal bag 52 of the cylinder wall 50a of the blow-molded product 50, the cutter 40 rotates toward the initial rotation position while protruding inside the cylinder wall 50a, and then moves to the outside of the cylinder wall 50a. When the cutter 40 is moved backward, the cutter 40 moves toward the initial rotation position even in a situation where the non-penetrating groove MA remains after the cutting operation is completed and the disposal bag 52 is not completely cut. It is possible to cut the disposal bag 52 by cutting the non-penetrating grooves MA remaining in the process of rotating.

Furthermore, by moving the holding members 14 and 16 holding the blow-molded product 50 to the cutting position and the retracted position with respect to the cutting device 30, the cutting device 30 can be accurately held at a predetermined position. That is, since it is possible to effectively suppress the oscillation of the rotation axis CR when the cutter 40 is rotated, the cutter 40 can more accurately cut the disposal bag 52 at the planned cutting position.

(Change example)
The embodiment is not limited to the above-described embodiment, and can be modified as follows, for example.
(1) In the embodiment, the holding members 14 and 16 can move to the cutting position and the retracted position by moving the holding members 14 and 16 toward and away from the cutting device 30. You may make it movable. Also, both the holding members 14, 16 and the cutting device 30 may be configured to be movable toward and away from each other.
(2) Although the cutting device 30 is provided with three cutters 40, the present invention is not limited to this, and any number of cutters 40 greater than or equal to two may be provided.
(3) In the embodiment, the cutting blades 40a are formed on both sides of the cutter 40 in the direction of rotational movement. A blade 40a may be provided.

36 moving body (advance/retreat moving part), 40 cutter, 40a cutting blade, 42 rotating part 50 blow-molded product (closed tube), 50a cylinder wall, 52 disposal bag (closed end), CR rotation axis

Claims (8)

A manufacturing device for manufacturing a tubular body by cutting a closed end of a closed tube,
a plurality of cutters spaced apart around the rotation axis and having a cutting blade at the end on the rotation axis side;
a rotating part that rotates the plurality of cutters around the rotation axis with the cutting blades facing toward the rotation axis;
an advancing/retreating moving unit that advances/retracts the plurality of cutters so as to approach and separate from the rotation axis;
In a state where the closed tube is held inside surrounded by the plurality of cutters, the cutter is rotationally moved around the rotation axis and moved forward so as to approach the rotation axis to cut the closed end of the closed tube. An apparatus for manufacturing a tubular body, characterized in that: By arranging the cutters at equal intervals around the rotation axis,
The cutter is rotationally moved by an angle equal to or greater than an angle obtained by adding a rotational angle from the start of rotational movement until the cutting blade penetrates the cylindrical wall of the closed tube to the arrangement interval angle of the cutter. 2. The apparatus for manufacturing a tubular body according to claim 1. The cutter is configured to rotate forward and backward about a rotation axis between an initial rotation position and a rotary cutting position by the rotating portion,
The cutter is rotated and moved forward from the initial rotation position toward the rotary cutting position to cut the closed end of the closed tube, and after the cutting blade is moved backward to the outside of the cylinder wall, the cutter is moved to the initial rotation. 3. The apparatus for manufacturing a tubular body according to claim 1 or 2, wherein the tubular body is rotated toward the position. The cutter is configured to rotate forward and backward about a rotation axis between an initial rotation position and a rotation cutting position by the rotating portion,
The cutter is moved forward while rotating from the initial rotation position toward the rotary cutting position to cut the closed end of the closed tube, and the cutter is rotated in a state in which the cutting blade protrudes inside the cylinder wall. 3. The apparatus for manufacturing a tubular body according to claim 1 or 2, wherein said cutting blade is moved backward to the outside of said tubular wall after being rotated toward said position. A manufacturing method for manufacturing a tubular body by cutting a closed end of a closed tube,
With the cutting blade provided at the tip of the cutter in contact with the outer surface of the cylindrical wall of the closed tube, the cutter is rotated around the cylindrical wall and moved forward so that the cutting blade penetrates the cylindrical wall. A method for manufacturing a tubular body, comprising cutting a closed end of a closed tube to manufacture a tubular body having an open end. The cutters are arranged at regular intervals around the axis of rotation, and the rotation angle from the start of rotation of the cutter until the cutting edge penetrates the cylindrical wall of the closed tube is added to the arrangement interval angle of the cutter. 6. The method for manufacturing a tubular body according to claim 5, wherein the rotary movement is performed by 6. After cutting the closed end of the closed tube, the cutting blade is retracted to the outside of the cylinder wall, and then the cutter is rotated to return to the initial rotation position. 7. The method for manufacturing the tubular body according to 6. After cutting the closed end of the closed tube, the cutter is rotated so as to return to the initial rotation position in a state in which the cutting blade protrudes inside the cylinder wall, and then the cutting blade is retracted to the outside of the cylinder wall. 7. The method for manufacturing a tubular body according to claim 5 or 6, characterized in that it is arranged to

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